Monitoring and controlling the energy consumption of a building, and in particular the energy consumption of an HVAC system, has been achieved through a BAS having software executable algorithms that incorporate numerical constant values corresponding to equipment operating characteristics. The equipment of the HVAC system may include, but is not limited to, chillers, pumps, condensers, filters, air conditioners, heaters, etc. The values utilized by the BAS are typically programmed during installation of the HVAC system and set according to the local climate and ambient conditions. These values may be changed periodically by manually evaluating and re-programming the BAS for anticipated changes in the local climate and ambient conditions.
Over time the local climate, ambient conditions and/or the operating characteristics of the building and HVAC system may change. For example, the operating characteristics of the HVAC system may change if a pump is replaced with a pump that has different characteristics. A more advanced type of BAS may utilize optimization software for controlling the HVAC system. This type of BAS will continue to adjust one or more operating parameters such that each piece of equipment is operating at or near its optimum to satisfy the building cooling load with minimal total energy consumption based on an equal marginal performance principle. However, the optimization software focuses on each piece of equipment such that periodically the numerical constants used in the optimization software may still need to be manually adjusted. This is typically done by recalculating the operating characteristics of the equipment, modifying the optimization software, restarting the BAS, observing the operational efficiency of the HVAC system and iterating until the overall operating efficiency of the HVAC system, as a whole, is within a desired efficiency.